Standard clinical and imaging-based small vessel disease parameters associated with mild stroke versus non-mild stroke.

Background: Mild stroke has variable outcomes, and there is an ongoing debate regarding whether the administration of thrombolytics improves outcomes in this subgroup of stroke patients. Having a better understanding of the features of mild stroke may help identify patients who are at risk of poor outcomes.

Objective: The objective of this study is to evaluate the association of clinical and imaging-based small vessel disease features (white matter hyperintensities and cerebral microbleeds) with stroke severity and clinical outcomes in patients with mild stroke.

Methods: In this retrospective study, mild stroke was defined as a National Institute of Health stroke scale (NIHSS) score <5. Clinical, laboratory and imaging data were compared between patients with mild stroke versus non-mild stroke (NIHSS≥5). Multivariate logistic regression analysis was performed to identify predictors of mild stroke and poor discharge outcome.

Results: Among 296 patients included in the study, 131 patients (44%) had mild stroke. On multivariate analysis, patients with mild stroke were three times more likely to have sensory symptoms [odds ratio (OR) = 2.9; 95% confidence interval (CI) = (1.2-6.8)] and four times more likely to have stroke due to small vessel disease (OR = 3.7; 95%CI = 1.4-9.9). Among patients with mild stroke, higher age (OR = 1.1; 95%CI = 1.02-1.1), presence of cerebral microbleed (OR = 4.5; 95%CI = 1.5-13.8), vertigo (OR = 7.3; 95%CI = 1.2-45.1) and weakness (OR = 5.0; 95%CI = 1.2-20.3) as presenting symptoms were more likely to have poor discharge outcome.

Conclusion: Sensory symptoms and stroke due to small vessel disease are more common in mild stroke than non-mild stroke. Among patients with mild stroke, presence of cerebral microbleeds on imaging and symptoms of muscle weakness are associated with poor discharge outcome. Larger studies are needed to assess the impact of cerebral microbleed on mild stroke outcomes and risk stratify the benefit of thrombolytics in this group.